Then a trench itself needs be considered. How huge is does the trench should be, how deep? Trenches over 5 foot need assistance either from sloping, shoring or trench box. You can certainly it \s over 20 foot deep the assistance to the side of the trench needs to be produced by a certified professional engineer. How can the trench be accessed? by ladders, actions or does it require a ramp? There need to be safe access within 25 feet of workers all the time, in case of emergencies. There may also be the need to check the environment from the trench for low oxygen levels or poisonous gases. Trench boxes are articulated to permit simple installation; nevertheless this causes it to be unsafe to stack the boxes together.